China's internet censors appear to be upping their game when it comes to stopping the country's more than 730 million netizens from bypassing the Great Firewall, online activists told RFA on Thursday.

As the ruling Chinese Communist Party carries out a nationwide security clampdown ahead of its five-yearly national congress in Beijing on Oct. 18, many circumvention tools used to view content and social media on blocked overseas sites seem to be failing, they said.

According to a social media post by online free speech activist Xiucai Jianghu, many people in China are increasingly unable to access sites like Twitter and Facebook using virtual private networks, or VPNs.

"A lot of circumvention apps aren't starting up," he wrote. "It's a shame. Technology is supposed to be used to improve people's lives, yet they are using it to suppress the truth and do harm."

A Tianjin-based internet user told RFA in a recent interview that he has recently had problems using the commercial version of the Lantern circumvention tool to "scale the wall."

"I use a paid VPN service," he said. "I had just paid two years' subscription in advance, not so long ago."

"But the very next day, it cut out ... and I haven't been able to get onto it at all in the past few days ... this is even affecting overseas service-providers."

Lantern uses peer-to-peer networks to connect people in uncensored areas who share their internet connection and servers to those in censored areas.

The Tianjin internet user said many other people have reported similar problems.

"A lot of other people haven't been able to climb the wall for several days now," he said.

WeChat outages

Users posted similar complaints to the social media site WeChat, with some saying the outage had stopped them carrying out their professional and business activities.

Rights activist Zhao Wei said he has tried a number of methods in recent days, but to no avail.

"First, I was hearing that other people weren't managing to get over the Great Firewall, but I was able to do so the whole time, and get onto Twitter," Zhao said. "But then suddenly, yesterday, I couldn't scale the wall whatever I did."

"I wanted to look something up, but I couldn't get around the censors."

He added: "This is terrible; it's like they've gone totally crazy."

China Rights Observer activist Xu Qin said the authorities appear to be targeting the internet access of specific individuals in their homes, as they place rights activists and dissidents under surveillance and house arrest ahead of the 19th Party Congress.

Xu said fellow rights activist Wu Lijuan had had her home internet access cut off twice in recent days.

"She posted a photo for me to see, but it's hard for me to get online right now as well," Xu said. "My home wi-fi keeps cutting every few minutes ... and it's very hard for me to get a mobile data connection, let alone get over the Great Firewall."

Controls may continue

Xu said the authorities are taking great pains to clamp down on any form of public criticism ahead of the congress, where President Xi Jinping is expected to further shore up his personal power and prestige.

However, there are also concerns that heavy-handed internet censorship may simply remain in place after the congress is over, Xu added.

Ever-tightening online controls have prompted a boom in VPNs imported to China by returning Chinese travelers, who download and install them overseas, ready for use back home, the South China Morning Post reported recently.

The Wall Street Journal reported on Thursday that China's powerful Cyberspace Administration has been in talks with major internet service providers including Tencent, Sina, and the video-sharing site Youku Tudou with a view to taking a one percent government stake in the companies and further boost control over the internet and social media.

Bruce Lui, senior journalism lecturer at Hong Kong's Baptist University, said such a move would increase the role of the Chinese Communist Party in policing the internet from within, but would affect those companies' image in international markets.

"Many of these internet companies have overseas interests, but have already run into obstacles because people fear that the government might be acting behind the scenes of these companies, using them for communications or state security purposes," Lui said.

"For the government to take a stake in these companies would make that relationship even more obvious."Reported by Yang Fan and Gao Feng for RFA's Mandarin Service.Translated and edited by Luisetta Mudie.